Lucy Maud Montgomery, who died in 1942, touches on darker themes including 'adultery, illegitimacy, misogyny, revenge [and] murder' in The Blythes Are Quoted. (Canadian Press)

Penguin Canada says it will publish the final volume of the Anne of Green Gables series in its entirety for the first time ever.

The Blythes Are Quoted was slated to be the ninth title in Lucy Maud Montgomery's popular series about head-strong orphan Anne Shirley, but it was never published during the author's lifetime.

A shortened version of the book — which left out about 100 pages of poems, short stories and vignettes — was published in 1974.

Now, Penguin says it will release the entire book this October, which will feature 15 short stories about Anne, as well as poems that Montgomery concocted "by" the heroine and her son Walter, who dies during the First World War.

Penguin said the book, set before and after the war, has Montgomery "experimenting with storytelling methods in ways she had never attempted before."

Montgomery, who died in 1942, blends dialogue, prose and poetry in the book.

According to the announcement, The Blythes Are Quoted could surprise a few Anne fans with its dark themes of "adultery, illegitimacy, misogyny, revenge, murder, despair, bitterness, hatred, and death — usually not the first terms associated with L.M. Montgomery."

The Anne of Green Gables series of books hit its 100-year anniversary in 2008. The original book, first published in June 1908, has since been translated into 33 languages.

A prequel — Before Green Gables by Budge Wilson — was published last year with the consent of Montgomery's heirs.

There have been two movies for the big screen, six for television and three TV series. The Charlottetown Festival's stage version of the story is the longest-running musical in Canadian history.